Figure 4. Mock-up of Web Radio (example of a program about Edgard Varèse's Déserts.The mainstream alternates interviews and musical excerpts (represented by the two colors). It allows the lis-tener to access the full source documents used by the producer (here, an excerpt of Le Sacred duPrintemps provides access to the full recording, represented by a longer horizontal bar below).Thelistener-spectator can thus navigate between a main stream and stored streams. In addition, he canappropriate himself any stream by annotating it; here, four lines of annotations mark excerpts fromthe program for different reasons (favourites, important citations, thematic indexation...).

A view of the Multimedia Library, as seen inits virtual 3D interface (http://mediatheque.ircam.fr/infos/vrml/index-e.html)

24 These are not necessarily functional objects, but models of what a finalised tool should look like after adequate

development, allowing experts to test their ideas visually and aurally in a collaborative way.

25 New communication and information technologies in the music classroom, coordinated by the AEC (Association